Normal healthy iceberg lettuce in the top of the photo and sclerotia-caused lettuce drop disease below.
Sclerotia damage at the bottom of an iceberg lettuce head.
S. SCLEROTIORUM fungus can germinate from mushroom-shaped structures which release large amounts of aerial-borne spores that cause high rates of lettuce drop disease. Photo by Jack Kelly Clark, courtesy of UC Statewide IPM Program.
Mike Matheron, University of Arizona plant pathologist, says a repeat performance of aerial-born S. sclerotiorum sclerotia this winter in lettuce is unlikely.
John Boelts, Yuma, Ariz. farmer, calls “devastating” the outbreak of aerial-born S. sclerotiorum fungus in Yuma County winter lettuce fields last season.